Buffing out Scratches in Composite Rails

Scuffed post sleeve caused when fitting bottom rail that was a bit snug.

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Plastic and composite railings have very uniform shiny or matt finishes that highlight scuffs and scratches. We take extra care when working with the parts to avoid damaging the finish but inevitably there are a number of mars that have to be addressed at the end of a large deck job.

When wrapping up a deck job we use a technique I learned painting cars as a kid. Automotive rubbing and polishing compounds are super-fine gritty pastes that buff out blemishes in seconds. And though it’s hard to buff away a deep scratch, the compound blends it in so it’s hardly visible.

Generally polishing compound can handle light scuffs and blemishes. Rubbing compound has a slightly more aggressive grit than polishing compound and will take out scratches and heavy scuffing. And after working out scratches or heavy scuffing with rubbing compound it may take a few rubs of polishing compound to match the sheen level of the railing.

We usually rub out the scuffs and scratches working the compounds by hand with a clean rag though it is feasible to use a buffing head on a random orbital sander or angle grinder.

Scuffed post sleeve caused when fitting bottom rail that was a bit snug.

Polishing compound used to buff out auto finishes is rubbed onto the scuff with a clean rag.